PubMed · 12077942
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
Mary Hampshire. Muscle bound.. https://pubmed.ncbi.nlm.nih.gov/12077942/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
Some adolescent and young males are engaged in misuse of anabolic-androgenic steroids (AASs) in connection with multiple drug use, in order to become intoxicated and brave, apart from currently known motives connected to sports performance and physical appearance. Recent studies suggest that alterations in neurobiological circuits implicated in the regulation of reward-related learning, aggression and motoric behavior underlie the behavioral changes associated with AAS misuse. We have previously shown that AASs induce alterations in dopamine receptor densities. The aim of the present study was to investigate if these effects could be attributed to altered mRNA content for tyrosine hydroxylase, L-amino acid decarboxylase, dopamine D(1)- and dopamine D(2)-receptor as measured by in situ hybridisation. Male Sprague-Dawley rats were subjected to 2 weeks of treatment with daily intramuscular injections of the AAS nandrolone decanoate at three different doses (1, 5 and 15 mg/kg/day). Results of the in situ hybridization showed that the mRNA content of the dopamine D(1)-receptor subtype was significantly reduced at all doses in the caudate putamen and at the highest doses in the nucleus accumbens shell. The mRNA expression of the dopamine D(2)-receptor was significantly increased at the two lowest doses in the caudate putamen and the nucleus accumbens shell. In conclusion, nandrolone has been shown to affect the expression of gene transcripts of dopaminergic receptors possibly implicated in underlying mechanisms of reward-related behavioral changes among AAS misusers.
The effects of anabolic-androgenic steroid administration on the function of the sarcoplasmic reticulum (SR) pump were investigated in chemically skinned fibres from the extensor digitorum longus (EDL) and soleus muscles of sedentary rats. Twenty male rats were divided into two groups, one group received an intramuscular injection of nandrolone decanoate (15 mg x kg(-1)) weekly for 8 weeks, the second received similar weekly doses of vehicle (sterile peanut oil). Compared with control muscles, nandrolone decanoate treatment reduced SR Ca(2+) loading in EDL and soleus fibres by 49% and 29%, respectively. In control and treated muscles, the rate of Ca(2+) leakage depended on the quantity of Ca(2+) loaded. Furthermore, for similar SR Ca(2+) contents, the Ca(2+) leakage rate was not significantly modified by nandrolone decanoate treatment. Nandrolone decanoate treatment thus affects Ca (2+) uptake by the SR in a fibre-type dependent manner.